Re: Not protecting Lisp objects from GC

[Jeremy Bryant]

Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> Jeremy Bryant <jb@jeremybryant.net> writes:
>
>
>> and care a lot about Emacs.
>
> To _very_ varying degrees over the decades, including two with zero
> interest. It's a long story :-).

I hear it's a long story.  After first using Emacs in the 90's, I
discontinued for unfathomable reasons.  I also therefore missed the
Emacs releases you did as maintainer.  I was recently studying the
xdisp.c code, to which M-x vc-annotate tells me you made large
contributions around 1999-2001 at least.  I find your code comments
helpful to learn about the code.  Thanks for that.

Emacs itself is also a long story.  It takes time to work on large
features.


>> I am a non-expert in GC.
>> As such would you have any guidance on how to
>> understand the benefits of the igc branch
>
> I recommend starting with admin/igc.org. I'm not a particularly good
> explaining things, but I'd hope it's helpful anyway.
>
>> and the 'easiest' entry points into the code for study purposes?
>
> MPS is a library, so one has to understand its API first; igc.org has
> links to the MPS documentation. The documentation includes a Guide that
> I would start with.
>
> Once you've done that, read the rest of igc.org, and then see how igc.c
> uses the API. I'd start here
>
> igc.c:
>  5235 void
>  5236 init_igc (void)
>  5237 {
>  5238   /* Returns previous handler.  */
>  5239   (void) mps_lib_assert_fail_install (igc_assert_fail);
>  5240   global_igc = make_igc ();
>  5241   add_main_thread ();
>  5242   set_state (IGC_STATE_USABLE_PARKED);
>  5243 }
>
> This is called very early when Emacs starts. It sets up everything so
> that the GC is usable. Follow the call tree and look up MPS API
> functions being called in the MPS Reference.
>
> Then ask questions :-).

Thanks for the detailed description and guide.  I will read up and try
to ask questions.

Furthermore this succinct summary and entry point may
help guide others now, on the road to this large feature.